The present invention relates to a method for bonding extrusion-molded or die-molded pieces such as automotive weather strips, and an apparatus for bonding such molded pieces.
As a method in which two extrusion-molded pieces, such as automotive weather strips, having hollow portions with the same sectional shape, are bonded with each other while end portions of the molded pieces facing with each other are made to abut against each other, there is known a method as follows. That is, as disclosed in JP-A-7-314560, a thin bonding raw material the sectional shape of which substantially coincides with the shape of the end surface of each of a pair of extrusion-molded weather strips is pasted onto the end surface of one of the weather strips to be bonded with each other. Then, the end surface of the one weather strip is made to abut against the end surface of the other weather strip through the bonding raw material. And then, the two weather strips are set in a mold and both the end portions thereof to be bonded are vulcanized and bonded with each other.
It had been required to insert an inner core between hollow portions of two weather strips to be bonded to prevent a molding material from being injected into the hollow portions. According to the aforementioned method, however, such an inner core becomes unnecessary.
According to the bonding method disclosed in JP-A-7-314560, however, there is a problem that the work of bonding is troublesome because the shape of the thin bonding raw material is formed to substantially coincide with the shapes of the end surfaces of the weather strips to be bonded with each other.
Therefore, to take measures to solve this problem, the following bonding method can be considered. That is, in the method, a sheet material 1 as a bonding medium is interposed between hollow extrusion-molded pieces 2 and 3, and the sheet material 1 is cut along the shapes of the end surfaces of the extrusion-molded pieces 2 and 3 to be bonded by a cutting blade 7 and a blade bearing portion 8 formed in upper and lower molds 5 and 6 so that a surplus of the sheet material 1 is removed, as shown in FIGS. 22 and 23.
In more detail, each of the upper and lower molds 5 and 6 is designed so as to split to left and right molds. That is, the upper mold 5 is constituted by split molds 5A and 5B, while the lower mold 6 is constituted by split molds 6A and 6B. First, an abutment plate (not shown) is put as a partition between the left and right split molds 6A and 6B, and the extrusion-molded pieces 2 and 3 precisely cut in a direction perpendicular to their longitudinal axes are set on the lower molds 6A and 6B so that the end surfaces of the molded pieces 2 and 3 to be bonded are brought into contact with the abutment plate from left and right sides, respectively. Here, the extrusion-molded piece 2 is set on the lower mold 6A and the extrusion-molded piece 3 is set on the lower mold 6B in the same manner. The distance between the extrusion-molded pieces 2 and 3 is defined by the abutment plate.
Next, the upper molds 5 (5A and 5B) are moved down and the molds are closed so as to clamp the extrusion-molded pieces 2 and 3 from their top and bottom. Thus, the extrusion-molded pieces 2 and 3 are held firmly. Then, the upper and lower molds 5A and 6A holding the extrusion-molded piece 2 and the upper and lower molds 5B and 6B holding the extrusion-molded piece 3 are moved to left and right so as to leave each other, respectively. Subsequently, in place of the abutment plate, the sheet material 1 is inserted between the end surfaces 2a and 3a of the extrusion-molded pieces 2 and 3 to be bonded, respectively (see FIG. 22).
Next, the upper and lower molds 5A and 6A and the upper and lower molds 5B and 6B apart from each other are made close to each other, respectively, and the end surfaces 2a and 3a of the extrusion-molded pieces 2 and 3 to be bonded are made to abut against each other through the sheet material 1. As a result, the sheet material 1 is cut into a shape (in FIG. 23, a circular shape) corresponding to the shapes of the end surfaces of the extrusion-molded pieces 2 and 3 to be bonded by the cutting blade 7 and the blade bearing portion 8 formed in the upper and lower molds 5 and 6. Then, the sheet material 1 and the extrusion-molded pieces 2 and 3 are heat-vulcanized so as to be bonded with one another (see FIG. 23).
Upon completion of bonding, the upper and lower molds 5A and 6A and the upper and lower molds 5B and 6B are made to leave each other. Further, the upper molds 5A and 5B are made to come off from the lower molds 6A and 6B respectively, and the sheet material 1 and the extrusion-molded pieces 2 and 3 molded integrally are taken out from the molds, thus removing tailings of the cut sheet material 1.
Thus, the bonding of the extrusion-molded pieces 2 and 3 is completed.
However, the above-described method of cutting the sheet material 1 with the cutting blade 7 and the blade bearing portion 8 formed in the upper and lower molds 5 and 6, the portion to be cut cannot be cut perfectly so that a burr 9 is produced in the outer circumference of the sheet material 1 cut along the shapes of the end surfaces of the extrusion-molded pieces 2 and 3 to be bonded, as shown in FIG. 24. When such a burr 9 is formed, there is a problem that a water-stop seal function is blocked when the extrusion-molded pieces 2 and 3 integrated with each other are used as seal material such as an automotive weather strip or the like.
It is therefore an object of the present invention to provide a method and an apparatus for bonding two extrusion-molded pieces, two die-molded pieces, or one extrusion-molded pieces and one die-molded piece, in which no burr is produced in any portion where the molded pieces are bonded with each other, and which facilitate the bonding work.
Other objects and effects of the present invention will become apparent from the following description.
The above-described objects of the present invention have been achieved by providing the following methods and apparatus.
(1) A method for bonding molded pieces, comprising the steps of:
providing a mold which can be split into left and right molds, said right mold having a cutting blade formed on a left side thereof so as to be along outer circumferential surfaces of the molded pieces, and said left mold having a blade bearing portion formed on a right side thereof for bearing said cutting blade;
setting a pair of molded pieces having sectional shapes coincident with each other into said left and right molds, respectively, in such a manner that end surfaces of said molded pieces to be bonded are put inside so as to face each other, wherein said pair of molded pieces each individually being an extrusion-molded piece or a die-molded piece;
attaching said left and right split molds with each other while inserting a sheet material acting as a bonding medium therebetween, so that said end portions of said molded pieces to be bonded are brought into contact with each other via said sheet material, and that said sheet material is cut into a shape along the shape of said molded piece end surfaces by said cutting blade;
applying heat to at least a portion of said molded pieces to integrate with each other; and
sliding at least one of said molds and said integrated molded article to move left or right.
(2) The method for bonding molded pieces according to item (1) above, wherein said mold, which can be split into left and right molds, can be further split into two or more molds in the vertical direction, and said sliding step is carried out by sliding at least each one of said vertically split molds of said left and right molds.
3. A method for bonding molded pieces, comprising the steps of:
providing a mold which can be split into left and right molds, said right mold having a cutting blade formed on a left side thereof so as to be along outer circumferential surfaces of the molded pieces, said left mold having a blade bearing portion formed on a right side thereof for bearing said cutting blade, and said cutting blade and said blade bearing portion being movable Left and right independently of said molds;
setting a pair of molded pieces having sectional shapes coincident with each other into said left and right molds, respectively, in such a manner that end surfaces of said molded pieces to be bonded are put inside so as to face each other, wherein said pair of molded pieces each individually being an extrusion-molded piece or a die-molded piece;
attaching said left and right split molds with each other while inserting a sheet material acting as a bonding medium therebetween, so that said end portions of said molded pieces to be bonded are brought into contact with each other via said sheet material, and that said sheet material is cut into a shape along the shape of said molded piece end surfaces by said cutting blade;
applying heat to at least a portion of said molded pieces to integrate with each other; and
sliding said cutting blade and said blade bearing portion to move left.
(4) The method for bonding molded pieces according to item (3) above, wherein only a part of said cutting blade and said blade bearing portion each along the outer circumferential surfaces of said molded pieces is made movable.
(5) The method for bonding molded pieces according to any one of items (1) to (4) above, further comprising:
slightly releasing a clamping force of said molds with respect to said integrated molded article, prior to said sliding step; and
tightening said molds after said sliding step.
(6) An apparatus for bonding molded pieces, comprising:
a mold which can be split into left and right molds adapted so that a pair of molded pieces to be bonded having sectional shapes coincident with each other can be respectively set therein with end surfaces of said molded pieces to be bonded being put inside so as to face each other;
a sheet material setting mechanism for inserting a sheet material acting as a bonding medium between said left and right molds;
a sliding blade portion which has a cutting blade disposed at a front end thereof for cutting said sheet material along shapes of end surfaces of said molded pieces to be bonded and set in said molds, said cutting blade being formed so as to be along outer circumferential surfaces of said molded pieces on a left side of said right mold, and said sliding blade portion being movable to left and right inside said right mold;
a driving mechanism for moving said sliding blade portion to left and right;
a sliding blade bearing portion which has a blade bearing portion at a front end thereof for bearing said cutting blade, said blade bearing portion being formed on a right side of said left mold so that said blade bearing portion, and said sliding blade bearing portion being movable to left and right inside said left mold; and
a spring member for pressing said sliding blade bearing portion to right.
According to item (1) of the invention, two extrusion-molded pieces (which may be replaced by two die-molded pieces or a combination of an extrusion-molded piece and a die-molded piece) are set in left and right split molds, so that end surfaces of the molded pieces to be bonded face each other. The molded pieces are bonded integrally with each other through a sheet material which is to be cut by a cutting blade. Then, the integrated molded pieces or the integrated molds are slid and moved to left or right, respectively. Accordingly, any burr of the sheet material in the outer circumferential surfaces of the molded pieces produced when the integration before the sliding is leveled by plane portions of the molds.
Therefore, when the thus integrated molded article is used as a seal material such as an automotive weather strip or the like, there is no fear that a water-stop seal function is blocked. In addition, because any burr is leveled, the appearance of the molded pieces becomes excellent.
Further, the sheet material as a bonding medium is cut along the shapes of the end surfaces of the molded pieces to be bonded by the cutting blade when the molds are integrated with each other. Accordingly, it is not necessary to cut, in advance, the sheet material along the shapes of the end surfaces of the molded pieces to be bonded. Thus, the bonding workability is improved
In addition, for example, when molded pieces each having a hollow portion are bonded with each other, it is not necessary to insert an inner core into hollow portions to be bonded with each other in order to prevent molding material from being injected into the hollow portions.
According to item (2) of the invention, in addition to the operation and effect of the invention stated in claim 1, the left and right split molds can be further split respectively into two, for example, vertically. Thus, by merely sliding and moving the upper mold of the left molds and the upper mold of the right molds, any burr can be removed not from the whole of the molded pieces but from only a required portion thereof. It is therefore possible to remove or level a burr in concentration from only a portion where a burr is apt to be produced.
Further according to items (3) and (6) of the invention, two molded pieces are set in left and right split molds, so that end surfaces of the molded pieces to be bonded face each other. The molded pieces are bonded integrally with each other through a sheet material which is to be cut by a cutting blade. Then, the cutting blade and blade bearing portion are slid and moved to left. Any burr of the sheet material on the outer circumferential surfaces of the molded pieces produced when the integration before the sliding is cut by the cutting blade similarly to item (1). In addition, the burr is leveled by a plane portion of the cutting blade.
Accordingly, in addition to an effect similar to that according to item (1) of the invention, an additional effect can be obtained as follows. Since a burr is cut by moving only the cutting blade and the blade bearing portion, if the cutting blade and the blade bearing portion are provided inside the molds as stated in item (6), the apparatus as a whole can be made compact to save a space.
Item (4) of the invention has the following feature in addition to the operation and effect of the invention stated in item (3). Only some part of the cutting blade and the cutting blade bearing portion formed along the outer circumferential surfaces of the molded pieces is movable. Accordingly, any burr can be removed not from the whole of the molded pieces but from only a required portion thereof. It is therefore possible to remove (level) a burr in concentration from only a portion where a burr is apt to be produced.
According to item (5) of the invention, the molds are released slightly from clamping the integrated molded pieces before sliding and moving in items (1) to (4) of the invention. Accordingly, the molded pieces, the molds or the cutting blade can be slid and moved smoothly. In addition, after such sliding and moving, the molds are closed again. Accordingly, any produced burr is leveled surely.